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A Simultaneous X-Ray and Optical Study of Tt-Arietis
Stecklum, B.; Toth, I.; Richter, G. A. +21 more
Prelimary results of an extended program of coordinated X-ray and optical observations of TT Ari are presented. The object was observed on August 21/22 1985 both in X-rays (EXOSAT) and optical range, about 100 days after the return to the active state. The first detailed simultaneous study of TT Ari in active state indicates the presence of strong…
IUE Observations of Hl-Canis and the Winds of Cataclysmic Variables
Raymond, J. C.; Mauche, C. W.
As evidenced by the P Cygni profiles of their ultraviolet resonance lines, cataclysmic variables—like early-type stars—are known to have extensive, high velocity winds. Assisted by AAVSO visual data andIUE ultraviolet spectra, we present an observational and theoretical study of the P Cygni profiles of the dwarf nova HL CMa. As these profiles are …
Hot Wind in the Double Degenerate System Am-Canum
Kjeldseth-Moe, O.; Solheim, J. -E.
The close binary system Am CVn consists of two helium white dwarf stars in close orbit. Strong flickering in the optical light curve and the observed spin-up in the rotation period indicate that mass transfer takes place (Solheim et al., 1984). The optical spectrum shows broad helium absorption lines (Robinson and Faulkner, 1975) sometimes partly …
Combined satellite and ground-based observations of the quiescent, high latitude symbiotic variable AG Draconis=BD+67°922
Lambert, D. L.; Cassinelli, J. P.; Anderson, C. M. +1 more
Satellite observations, fromEinstein,IUE, andIRAS, have been combined with ground-based observations to derive the quiescent energy distribution of the symbiotic star AG Draconis. A detailed comparison is made between the combined observations and various steady-state composite models, including blackbody accretion disks.
X-Ray Observations of Cataclysmic Variables
Osborne, J. P.
The X-ray observatory EXOSAT spent over 1000 hours observing cataclysmic variables. Some of the major results reviewed here are: soft X-ray light curve changes in AM Her objects, orbital effects in the X-ray light curves of intermediate polars and U Gem, regular behaviour in the inter-outburst X-ray flux of VW Hyi, and X-ray emission from the tenu…
A photometric and spectroscopic comparison of the cataclysmic variables on the 2 sides of the period gap and at a specific orbital period
Szkody, P.
New and previously existing photometric colors and spectroscopic H and He line strengths are used to compare CV disk systems below the period gap (P=80–130 min) with those directly above (P=190–240 min). Significant differences are found in the mean U-B, V-J colors and in the Hß equivalent widths on the 2 sides of the gap. A detailed comparison fr…
EXOSAT Medium Energy Observations of CYGNUS-X-2 Spectra and Qpos
Maraschi, L.; Tanzi, E. G.; Chiappetti, L. +3 more
We report on a series of observations of Cyg X-2 obtained with EXOSAT in September 1983 at five phases in a single orbital cycle (P=9.8 days, see Cowleyet al. 1979). Here we present spectral data obtained with the Argon counters of the Medium Energy experiment (ME) (see Turneret al. 1981), together with the search of Quasi Periodic Oscillations (Q…
The may 1985 Super Outburst of Oy-Carinae - Part Two - Phase-Resolved IUE Spectroscopy and EXOSAT Observations
Sonneborn, G.; van Paradijs, J.; Charles, P. A. +4 more
We present ultraviolet and X-ray observations of the eclipsing SU UMa dwarf nova OY Car early in the decline from a superoutburst. From the UV emission line spectrum and lack of X-ray eclipse, we deduce the presence of an extended coronal region.
X-Ray and Optical Observations of the X-Ray Source EX:0020528+1454.8
Richter, G. A.; Hudec, R.; Goetz, W. +7 more
We present preliminary results of the EXOSAT X-ray observations and quasisimultaneous and simultaneous optical photometry of the X-ray source EX0020528+1454.8=1E0205+149 found independently as an serendipitous source both with Einstein and EXOSAT satellites. The optical counterpart is a pair of dMe stars. Our results indicate that the object is va…
X-Ray and Ultraviolet Observations of Ag-Draconis during Quiescence and Outburst
Piro, L.; Córdova, F. A.; Friedjung, M. +3 more
We describe the first X-ray monitoring of a symbiotic star during phases of enhanced activity. AG Dra is a Pop II object with a composite spectrum, characterized by a cool K-type component, prominent high ionization emission lines and a strong UV continuum which is attributed to a hot dwarf companion. Periodic variability of the UV radiation durin…